How should I mount this grinding stone?

I've added a swing-down ID grinding spindle on my cylindrical grinder and am slowly learning how to use it, mostly by trying things.

I would like some advice about how to mount this stone (30mm diameter) on this arbor (23mm). I want to be able to face grind with the outer rim, so a good mount would leave most of the inside space free.

The hole in the arbor has an unthreaded section 12.35mm diameter, followed by an M12 threaded section. The hole in the stone is about 13.5mm.

I can easily turn mounting hardware from steel and/or plastic, and also have blotter paper and epoxy on hand.

The simplest way to do this would be to just bolt the wheel to it. An M12 socket head screw long enough to reach past the 12.35 c'bore in the arbor, paper between the screw head and stone, and between the stone and arbor. I mount grinding wheels to our I.D. spindle at work this way daily. Turn down the screw head if it won't fit in the wheel counterbore. I have ground the head of the mine til I can just get an allen wrench in there, allowing the use of as much of the wheel face as possible.

I've added a swing-down ID grinding spindle on my cylindrical grinder and am slowly learning how to use it, mostly by trying things.

I would like some advice about how to mount this stone (30mm diameter) on this arbor (23mm). I want to be able to face grind with the outer rim, so a good mount would leave most of the inside space free.

The hole in the arbor has an unthreaded section 12.35mm diameter, followed by an M12 threaded section. The hole in the stone is about 13.5mm.

I can easily turn mounting hardware from steel and/or plastic, and also have blotter paper and epoxy on hand.

Looks like a stone I used to grind router bits. The hole was the wrong size so I stood them up on the drill press and made the hole bigger and counterbore deeper with using a carbide drill-bit..
Used a simple arbor like Plusminus drew and the job did well. Ran with a tool post grinder mounted in a small Ko Lee TC grinder.

Yes, used a blotter. used to get Routers by the thousands...They are very common in making plastic parts and because the jigs are hard, they (router bits) get nicked up often... good to fill the arbor bore with the 12.35 and 13.5 steps...and be sure the rotation tightens.

Thanks for the advice. I turned and threaded a "bolt" to hold it on. This is a good fit in the stone, but not tight, same for the portion that goes into the arbor:

The head is 3mm (1/8") thick. I used a rotary broach (made from Hemingway kits plans) to broach a 6mm hex socket hole for tightening it.

I tightened the stone between two blotters as much as I dared, and it held in place nicely and didn't blow up. I dressed the OD parallel for balance and the face at a few degrees inwards, so it would cut on the outer edge.

Then tried it out to dress a chuck mounting plate. It worked very well, especially considering that I am grinding dry. (Note to self: need to start sorting out how to use coolant here and how to prevent it from being blown all over the shop.)

end result had no visible run-out with a 2 micron (0.00008") per division indicator.

Cutting as intended on the outer edge:

I notice that the pattern is not a cross hatch, which suggests that the spindle axis is tilted up towards the workhead. Easy to realign, if that's the case.

[EDIT] I checked, and indeed the ID spindle axis is pointing up towards the workhead about 1 mm over 200mm. Will realign and try again.

I adjusted the ID grinder so that the spindle axis is parallel to the long axis travel in both the vertical and horizontal planes. I now get a nice cross-hatch pattern!

This time I dressed the face of the stone concave by hand with a Norbide stick. That worked well and is very quick. Previously I used a diamond dresser mounted on an adjustable ram.

I'm happy that the DRO on my machine has micron resolution for the long axis -- it's very useful for face grinding because you can come back exactly to a previous position or take off 1 micron at a time from the face. The grinder has a nice planetary gear switch on the long axis feed wheel. When engaged, one gets 2mm travel per handwheel revolution, so nudging a micron or two is possible.

small stones that mount on a id threaded brass tube, like the ones used for grinding valve seats.

I have made these up when i could not find a suitable size stone, i just bonded the stone to a old adaptor and was good to go.

I used Q bond to do it, just put a piece of alfoil under it and place it in the centre of stone as close you can, then pour in a thin layer of powder add superglue, repeat till you get it all filled up, both sides. alfoil is so it does not stick to the table....it sets rock hard.
Then all you do is thread it onto the adaptor then dress the stone.

If you don't like that method there is another by reform ( germany ) you place some red powder on the mount and heat it up on a hotplate, place the stone on it when its all good and hot take it off and let it cool.
it glues onto a face / face so needs surface area.

reform has the powder just order from them.

they use it on their knife grinders to mount the stones, they are only glued on...you can do it as many times as you like just add a little powder each time as it gets used

There is a little lip so the stone can be centred, to remove old stone you just heat it up again on the hotplate.

small stones that mount on a id threaded brass tube, like the ones used for grinding valve seats.

I have made these up when i could not find a suitable size stone, i just bonded the stone to a old adaptor and was good to go.

I used Q bond to do it, just put a piece of alfoil under it and place it in the centre of stone as close you can, then pour in a thin layer of powder add superglue, repeat till you get it all filled up, both sides. alfoil is so it does not stick to the table....it sets rock hard.
Then all you do is thread it onto the adaptor then dress the stone.

If you don't like that method there is another by reform ( germany ) you place some red powder on the mount and heat it up on a hotplate, place the stone on it when its all good and hot take it off and let it cool.
it glues onto a face / face so needs surface area.

reform has the powder just order from them.

they use it on their knife grinders to mount the stones, they are only glued on...you can do it as many times as you like just add a little powder each time as it gets used

There is a little lip so the stone can be centred, to remove old stone you just heat it up again on the hotplate.

That Q Bond looks interesting, I have a broken part that fits together well made of cast something. Might give the Q bond a try. Thanks.
Buck

Nice job Bruce...Did you mean to say Norbide stick as in Norton norbide....Or is there a Norbite stick?
I set a Norbide stick on the surface grinder chuck (boxed in) you can double tape it if worried and with a stop at the go end.....and grind one side with a 220 or 120 diamond wheel; straight across with long travel/no crossing. this makes the surface on one side smooth with 220 or 120 grit lines. Yes I down feed on the grind side and go slow across..no down feed on the climb side.. a slip of paper under will protect your chuck..very light /small down feeds..Then I break the corners edge with hand hone to a flat wetted dimond wheel.
This make a fine de-burr stone for SG parts and a good finish knife sharpener for the last pass after stoning...

Soon as I hit the Lotto, I will come visit your shop. Then go to visit Gordon in Denmark.

Street -- thanks for the suggestions regarding gluing stones. I have used cyanoacrylate glues with glass-sphere fillers before. Did not think about using them for this. Would be grateful for a link to the Reform heat-activated red glue - I could not find it with google.

Buck -- you are welcome to visit anytime! Yes, you are right, it is Norbide not Norbite. I have one little stick that was expensive but makes it real easy to dress stones by hand. I did not think about grinding it with a diamond wheel to get some texture. Interesting idea.

i don't think q bond will work with a broken part that fits perfectly back together, from my use it likes to have a gap so you can put the powder into then set it off with the glue.
I only do 3 mm layers and do it multiple times to get full depth of the part. I suppose it will also do fillets but have not tried that.
It sets really quick.

Reform is here this is the machine, i did not see the glue mentioned anywhere on the site, so you will have to ring them up about it and see if you can get a part number.
It looks like a reddish orange paste when fluid i think it may even be a version of a plastic with low melting temp.
Its used to mount their stones to their hubs on their grinders. The hub can be reused many times, you do not have to remove any of the old glue you just add a bit of powder each time as some gets wasted upon removing the old stone.
I don't know how temp will affect other types of stone from other manufacturers so you need to check that out if it affects the bond its no problem with reform wheels.

The wheel locates in a slight spigot so it is always reasonably central, you may need to redesign mount in a similar way with a spigot on od or id, only 2 -3 mm high nothing major just enough to align it.

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